Improvement in calls for telegraphs



Al Electrical-Relay Instrument.

Patented May '12, 1863.

Wa ZvI/as-sa-F I 4 MM UNITED, STATES ALEXANDER BAIN, or new P TENT? OFFICE.

ron n. Y, ASSIGNOR 'ro WM. H. Atrium-or SAME PLACE. i

IMPROVEMENT in CALLS, FOR' ,TELEG RAPHS.

Specification forming part of Letters Patent No. 38.529, dated May 12, 1863; antedated December 11, 1862.

Figure 1 is atop view of theimproved call,

which I term the f silentmessage call. Fig.2 is a central vertical section of the same.

Similar letters of reference indicate corresponding parts in both figures.

The custom now generally adopted in this country infelectric telegraphy of reading -intelligence by the sounds emitted by the instruments in their operation has rendered it difficult, if not impracticable, withthe instruments at present in common use, to transmit intelli:

gence with any degree of secrecy, for the instruments in all other offices or stations on a line of telegraph besides that to which the intelligence is to be transmitted, operating in unison with the instrument or instruments at that station, produce the same sounds, which may be heard by other persons than the confidential operator who may be familiar with the telegraphic alphabet and near the instrument or instruments. ure obviated this difliculty by means of the receiving-instrument which constitutes the subject-matter of Letters 'PatentNo. 1,850, dated July 23, 1861', but it is essentially necessary that the several offices or stations on a line should have means of communicating with each other by sounds .aud-ible at some considerable distance from the instruments, so that the operator at one office or station may draw the attention of him at any other which it may he wished to communicate with; and to this ,en'dthis invention consists inau instrument which, I term the silent message call, from which, though it is capable of callingthe attention of the operator, messages cannot be read, because the electric pulsations produced inthem-transmission are too frequent for its action, but'which, when the pulsations are less frequent, will actin accordance with them, and

I have in a great meas thereby produce sounds sullicientlyloud to be heard at a distance greater or-less, according to the strength of the electric currents, and

which sounds will then be intelligible and are intended to be used to call from one office or station to another.

To enable others skilled in the art to make and use myinvention, Iwillprocecd to describe its construction and operation.

A is a wooden stand having secured to it, one above another at a short distance apart, by pillars (J 0, two oblong reels or frames, '13

B, which are made of hard india-rubber or othe suitable non-conducting material covered or filledwith coils of fine copper wire covered with silk, and which resemble those commonly used in galvanometers.

E is a permanent steel-bar magnet, secured at the middle of its length on a horizontal axle, a, which is arranged to oscillate freely in bearings provided for it in two fixed pillars, F F, secured to the stand A on opposite sides of the reels B B, the said magnet being situate. within the reels and the said axle-between the two reels.

Attached to thepermanent magnet E is a weight, 0, composed-of a piece of wire, which is bent to a-position to compensate for-the dip of the magnet and balance it in a horizontal position when not influenced by currents of electricity passing through the coils of wire on the reels.

G is a glass disk secured above the reels by a screw, 0, passing through its center to 'a cross-bar, H, which is arranged across the upper reel, and whose ends are secured on the tops of-the pillars F F.

I I are the terminal screws for connecting the ends of the telegraph-conductor to the instrument. Two of the ends of thc reel-wires are secured together, and the other ends are secured to the terminal screwsI I, one to each screw.'

It will be observed that the permanent magnet E is placed in the same position as what is known as a dippingneedle -that is to say, the axle and the magnet are both in the same horizontal plane -so that when the needle IS deflected by the e ectric current passi g through the coils of wire on'thereels, but the duration 'of such currents and the intervals between them beingvery short; the magnet cannot complete it range of motion, partly on account of the influence of the magnetism of V the coils extending over a much greater ran ge than that'of an ordinary electro-maguet, such as is ordinarily used for telegraphic purposes,

whose chief magnetic power is at or close to the poles. Therefore the instrument, though it serves well enough as a call, will not make known any of the ordinary telegraphic coinmunications. i

This call is to he so arranged in the office or station in relation to the receiving-instru- 1nent, and with a brake so applied in connection with the two, that when the receiving-instrurnent is not desired to be in operation the latter may be shut off the circuit, the call being .in the meantime allowed to remain in'circnit.

What i claim as myinvention, and desire to secure by Letters Patent, is-

-' The call composed of the-reels of wire B B,

the permanent magnet E, and the glass disk G,

or its equivalent; the whole combined, applied,

and arranger] to operate'substantially as and for the purpose herein specified;

t ALEXANDER BAIN. Witnesses: I

4 R. GAWLEY, 7

JAMES LAIRD. 

